Box

Composes with the classes `Box` computes instead of replacing them.

The element it paints. Everything else about `Box` is style, so this is what decides its semantics: without it you get a `div`, which is right for a wrapper and wrong for anything a screen reader should announce. The DOM props it accepts follow from this.

Animates the element in when it first scrolls into view. `true` takes the catalogue entrance; an object tunes it — `preset`, `distance`, `spring`, `duration`, `once`, `amount`, `rootMargin` and `index` for a stagger. It lives here rather than on each surface so that `Card`, `Paper`, `GradientBorder`, `Section` and anything else built on `Box` inherit one implementation. Without it `Box` stays a server component; with it the root swaps for a client shell and the children keep rendering on the server. The entrance is a CSS transition, not a JavaScript animation: it is the only motion in the catalogue that fires WHILE the user scrolls, and the compositor should own it.